SCCAjunkie

After a few searches, some successful, I figured I document my work with a Holley Pro-jection system here. Please feel free to add thoughts, as questions, or contribute as you see fit. I certainly don't have the answers at this point, but I'm starting to figure out the right questions.

I'm going to list all my info, relevant or not, but I'll try to keep the thread itself to the TBI tuning specifically. The purpose of this car is multi-faceted. First and foremost, it is a "daily" driver. I have a truck, and another economy car (currently awaiting a reconstructed title though). Second, I am a track-day instructor, so this should be a decent car to have a good time and take students out in. Finally, as an ancilliary concern, I may run the car at time trial events as well. I formerly built a 90 Formula 350 for this same purpose, but never go to swapping in the T5, and eventually so the car (to the guy that built this one).

Stats on the car:

Chassis:
84 Camaro Z28 (formerly a L69 5sp car) hardtop
Stock struts (to be replaced with Koni Yellows that I have)
Stock springs cut one coil (soon to be replaced with ???)
Swaybars are 36H/22
Aftermarket rear LCAs
1LE brakes
Chassis reinforcement, a bar (or cage), and other stuff to come
16" GTA wheels (fronts on rear, rears on front with spacers, and yes, I have long ARP studs).

Drivetrain:
T-5 from the 84 car
aluminum flywheel
steel driveshaft
91 rear with 3.42s and a Torsen T2R

Engine specific (the important stuff):
L98 long block from a 91 Z- stock
Edelbrock Performer (I think) 4bbl intake
Holley Projection (2D I believe) 2bbl with closed loop
2" high air filter with solid lid (soon to be K&N 2.3" filter and X-treme lid)
HEI distributor with vac and mech advance- I'm told it's set to 12* base timing, full advace at around 2500
Stock L98 exhaust manifolds and crappy y-pipe (soon to be shorty headers)
3" mandrel exhaust, no cat, with Flowmaster 1-in/1-out
Fuel pump is the stock TBI in-tank pump- pressure not known but gauge coming soon

Baseline info-
Purchased the car in February. No feedback kit installed. Car was running decent. PO tells me that he did check the TPS voltage and set the idle stop according to Holloey Instructions (and I believe him). Did not document the **** settings at that point (BIG MISTAKE). As a side note, the standalone controller is mounted to the pass. side of the upper center console (near the radio). Documented milage for 2 tanks of fuel- roughly 12 mpg and 13 mpg respectively in mixed driving, with some, um, exercising of the car. I do live in a very hilly area of SE PA, and my commute of 20 miles has some hills, some flat, mostly back roads, a 1 mile stretch of stoplights, and a 2 mile stretch of highway.

Description of settings:
When I list my **** settings, I'll use the following format- Holley suggests that you start with the ***** at the midpoint of their travel. This would mean that if you had the controller bolted flat to a table in front of you, the slots in the ***** should be horizontal. I'll call this "center". Turning the **** clockwise would then put you "above center" and CCW would be "below center". I'll try to get an approximate position in degrees (such as 90* above center would mean the **** was turned clockwise and the slot is straight-up-and-down in our example).

SCCAjunkie

Update 1- where I am at so far

One evening, the car began running badly. This continued the next morning on the way to work- very boggy, wouldn't idle, seemed to load up. Tried changing the IDLE setting to correct the idle, and no success. About 3/4 of the way to work, I realized that the MAIN **** was turned all the way up. Thus began the process of "messing with *****" to try to restore things.

Got the car to run decent (still working on it) with the following settings after a week of experimentation-
MAIN- roughly center, maybe the tiniest bit above
HIGH RPM- above center 90*
IDLE- 90* below center
ACCEL- 30* above center
CHOKE- 30* below center (still working on this)

Last Saturday, I installed the closed-loop kit. O2 sensor in the driver-side manifold fitting, wire through the speedo cable hole, then under the dash to the controller. Car ran OK on Sunday, but I was having a clutch issue (see thread in the Trans. forum- clutch pivot backed out). Fixed that. Didn't drive it Monday. Installed an Air/Fuel gauge on Monday night. Drove it yesterday. Ran like CRAP on the way to work, surging and bucking at light loads. Seemed OK, under throttle and idling, but crappy during what should be closed-loop. I assumed it had something to do with the Air-fuel gauge or something. I pondered it at work, then looked at the car before going home...

Placement of the 02 wire is CRITICAL. Apparently, having the 02 and air/fuel gauge wire running next to and parallel to a plug wire is BAD (which, since I used to teach electronics, I should know). I didn't realize I had done that, as I was trying to avoid other "hazards" in the engine bay. Relocated the wires, and it ran fine on the way home. The gauge, however, does not read correctly. At idle, it flickers all over the lean side of the gauge, then disappears with any throttle application. I need to check the ground for the gauge.

To Be Continued...

thomas1976

I would start looking for a vacuum leak, a bad sensor or a bad fuel pump.

Once the issue is solved, you should learn about your injectors flow #'s and adjust fuel pressure to match estimated hp.

If you would like to try one of the finest TBI engine manegments, check out http://dynamicefi.com/

SCCAjunkie

Thomas, thanks for the reply, but I'm not sure why I'd be looking for those things. It's obvious that the gauge is the issue, as the car runs well (have checked via plug cuts).

While I m looking into another controller in the future, the idea here was to document what I've gone through so that others might possibly benefit. With the current low prices for a used Pro-jection unit, it might be an appealing option for some...

thomas1976

I missed the spot were you figured out the issue, my apologies.

Can't waith to read the detailed fueling chapter

SCCAjunkie

Minor update-

Still have not fixed the A/F gauge. Checked power and ground. Next step is to actually solder the lead wire to the O2 harness (it's currently "tapped" with a splice connector).

The car runs very cold. The PO put in a 165* thermostat, with 3 steam holes. Temp never reaches the "second" line- makes it past the bottom of the gauge markings, then sits 1/2 way between the bottom line and the 2nd. I have a 180* thermostat to install, but I'd like to get the A/F gauge fixed so I can see if the computer is even making it into closed-loop mode.
Does anyone know- once the choke programs kicks off (idle drops to normal), does the computer immediately hit closed-loop, or does it have to hit a certain temp first? Again, this is the Holley Pro-jection 2D computer, not the stocker.

Still not getting above 13 mpg as of last fill up, but the current tankful is looking better. Only change- dialed back the MAIN **** to just below center.

K&N X-treme lid and filter installed, on a base that is less drop than the other one.

Current **** settings after more tweaking-

MAIN- 5* *below* center now
HIGH RPM- above center 45*
IDLE- 90* below center
ACCEL- 30* above center
CHOKE- 30* below center

I intend to do a bit of work over the next week or so.

8t2 z-chev

i ran holley pro jection on my z28 for a couple weeks
around 1992-ran good most of the time,but my setup
-the pro-jection on stock carb manifold using adaptor-
had very bad part throttle mixture distribution...
Stock TBI fuel pump is probably not up to the job-
should upgrade that.

Ronny

iTrader: (1)

Yes the coolant temp has to hit a predetermined temp. generally 155-165dF. A 180 term is a good idea.

Does not Holley offer datalogging to see how far off tune is? If not then run winALDL and locate a ALDL cable.

that A/F guage is pretty much useless. It follows the swing over stoich rich lean rich lean rich lean. a datalog will show swing as well. Just tells you you are in CL but a flag in winALDL does same

SCCAjunkie

Does anyone know specifically what the temp threshold is on the Holley standalone unit?

I cannot run WinALDL or any other datalogging through the stock computer because it isn't there. I burned chips for my old TPI setup, so I assume I understand what you're getting at. If I am missing something, please let me know. This setup is ONLY run by the little Holley Pro-jection 2D control box, which has 5 dials to adjust. I'm not aware of any way to get data out (not saying it's not possible, just that I don't know).

As far as tuning on an A/F gauge, I had VERY good luck using a combination of A/F gauge readings (before the days of widely-available wideband) and plug cuts on several turbocharged, carbed, and fuel injected cars. I think they can be a useful tool, and I had this one sitting around, so I figured I'd install it...

SCCAjunkie

Updates- Starting the process over again, as I've bolted on headers. The guy that did it for me messed with the idle position screw (the mechanical part that stops the throttle), so I'm going to start fresh.

Right now, I have a very high idle and a barely noticable surge at times. I've unplugged the feedback loop, as you're not supposed to run it unless your tuning is close (per Holley's instructions).

One thing I found out- it appears my A/F guage is not working completely correctly. If I unplug the feedback harness from the Holley ECU, the reading goes up sigificantly. I'm also not sure that it's really accurate at any time. I'm hoping this is the gauge and not the sensor. I'm assuming the sensor is mostly OK, since when I did have it hooked up previously, the car ran pretty well.

Prior to making these changes, the car was running decent, and I had made it up to 16 mpg... For those who would ask why I messed with it, the car was getting other work done (including pulling the trans since I took out the wrong plug), so it seemed like the perfect time to swap in the headers I had.

Of course, we're getting days of rain now after weeks without, so I may have some time before I get everything locked back in right.

SCCAjunkie

Dialed the idle screw back down (the mechanical on the front of the TB) and everything is back to running better.

I believe I have the MAIN just a bit *below* the last setting before the swap. Power delivery seems smoother than before, but a lot of that is that the engine doesn't seem to bottle up at 4000 RPM. Headers, even shorties, are a wonderful thing

If it continues to run well, it'll be back to closed-loop tomorrow.

As a note- with the idle screw (mechanical) turned up (and I know the TPS was not corrected), fuel consumption was very high. Not sure if this is typical, but it seems to be much better now. Perhaps the injection saw a TPS voltage that made it think it was off-idle. It's a little hard to reverse engineer that little box.

SCCAjunkie

Had a fuel pump issue that is now resolved, so I'm starting the whole process over again. I ditched the TBI pump in favor of the TPI pump (EP241). If you do install Projection on a healthy motor, USE THE TPI PUMP. Supposedly, the previous owner tried one and had leakage issues at the fittings and regulator so he went back to the TBI pump, but I have not seen these issues at all. The car pulls stronger on the high end now, so trust me, go to the better pump from the beginning.

Current status- car is driving well. Idle screw still set where it was before, but the car seemed to be finicky at idle when I installed the new pump. Just for giggles, I checked the TPS voltage- it was 0.48V. Holley recommends a little over 0.6V for throttle closed. I adjusted it, and viola, the car runs like a champ. I am still sorting out some minor things, but I'm headed in the right direction. Running under "choke" is not perfect. **** settings:

MAIN- 20* below center
HIGH RPM- above center 10*
IDLE- 10* below center
ACCEL- 10* above center
CHOKE- centered

Not the differences in high rpm and accel, which I would attribute to now having much more fuel available when needed because of the better pump.

thomas1976

Wasen't running that great after all

I was reading the tuning instructions, found it interesting.

http://www.holley.com/data/Products/...9777-6rev1.pdf
http://www.holley.com/data/TechServi...cal/R10022.pdf

SCCAjunkie

It was running reasonably well, but the fuel pump died. The strainer sock apparently was torn most of the way off, and finally sucked something and locked up.

I *still* have the issue with the air/fuel gauge.

I noticed that the A/F reading changes significantly when I unplug the closed-loop harness from the ECU. I'm probably going to install a second O2 sensor just for the gauge. Since I popped a collector gasket on Friday, I'll have the chance to weld in the second bung when I swap the gasket...

SCCAjunkie

New issue I've been working on for a few days.

The car has a stutter/surge at low RPMs, and hunts at idle. I first noticed it as the stutter in higher gears (4th and 5th) between 1500-2000 rpm. The idle surging showed up the next day, but seems to be related. I've done the following things in this order:

Check for vac leaks- found cracked line on the vac advance line, now fixed, and a split vac cap on the large front vac nipple, so I replaced all the other vac caps as well.
Checked TPS- still set at .62V with throttle fully closed.
Checked for loose suspension pieces- found panhard brace bolts (upper driver side connection to body) we not fully tight, got about 1/4 turn on each. Also see a crack in the torque arm bushing, so I'll be replacing that with poly finally.

After doing this, it's much better, but still showing slight symptoms.

On the list to do:
Replace torque arm bushing
check distributor for shaft play
check vac advance function and check for leaks
check mech advance
check fuel pressure

Any other thoughts?

SCCAjunkie

Now that I believe I've got things sorted again (they have been for a while, but it seemed like every time I posted a new issue would appear)-

The last issue was--- broken timing advance springs. I'm thinking that may have been an issue previously- as in one was broken- but I found that a month ago, and the car has been driving great since then.

Not sure how much longer I'll keep at the current Pro-jection setup though. I *believe* I'm at the upper limit of what it will support, as it seems to go lean above 5000 rpm. One disadvantage to this system is the lack of ability to data-log everything. The PO has offered me a Holley Commander system in exchange for the whole Pro-jection system back, so if I find another induction system, I may be switching. I have a whole stock TPI setup off my old car, but I cannot bring myself to use that now that I've seen the potential of the TBI setup. Aftermarket TPI is one thing, but I'm also feeling the desire to maintain the stock L69 "look" underhood...